I have a workspace which contains a PLMset object (from affyPLM package). When I read it, and then load the library affyPLM, I cannot visualise the residuals image, while if I load the library first, followed by the workspace, the image displays fine. More precisely: library( affyPLM ) load( "./Image.RData" ) image( Pset, which=1, type="resids" ) works fine, while load( "./Image.RData" ) library( affyPLM ) image( Pset, which=1, type="resids" ) returns the error: Error in image.default(Pset, which = 1, type = "resids") : argument must be matrix-like The function existsMethod( "image", "PLMset" ) returns TRUE in the first case, and FALSE in the second, while the function hasMethod( "image", "PLMset" ) returns TRUE in both cases. My question is: is there a way to force the display of the image in cases where I had loaded the workspace before the library ? Many thanks, Eric PS: > sessionInfo() R version 2.11.0 (2010-04-22) x86_64-apple-darwin9.8.0 locale: [1] C attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] affyPLM_1.24.0 preprocessCore_1.10.0 gcrma_2.20.0 [4] affy_1.26.1 Biobase_2.8.0 loaded via a namespace (and not attached): [1] Biostrings_2.16.2 IRanges_1.6.4 affyio_1.16.0 splines_2.11.0 -- Dr Eric Blanc Lecturer in Bioinformatics Tel: +44 (0)20 7848 6532 MRC Centre for Developmental Neurobiology King's College London New Hunt's House, Room 4.10B Guy's Hospital Campus London SE1 1UL